The proposed research entails the organ-level and tissue-level analysis of neocortex by ablation-behavior methods. The ultimate goal is to discover the contribution of sensory, association and motor cortex to the neurological and psychological adjustment of man to his environment. The short-range goals include the assessment of the roles of major areas of neocortex in a sequence of primitive mammals selected to approximate the extinct animals in man's ancestral lineage. In this manner the phylogenetic development of man's neocortex can be traced from its most primitive mammalian form to its current form in an attempt to understand the contributions of its many parts. Since surgical ablation duplicates the type of brain damage that often results from stroke, the inquiry also can be expected to yield information about the fragmentation of man's psychological capacities as a result of cerebrovascular accidents.